August 2008 - Boost-users - lists.preview.boost.org

test
by Sergey Sadovnikov 18 Aug '08

18 Aug '08

Hello All, test -- Best Regards, Sergey mailto:flex_ferrum@artberg.ru

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[Trac] Can not view tickets, can not report bug.
by John C. Femiani 18 Aug '08

18 Aug '08

I wanted to search tickets by library on the track site, but I got a trac error. The error had a link to create a ticket so I could report the Trac error to you guys, but then the ticket is rejected as SPAM! What am I to do? (I have another bug to report, but I can not even get far enough to see if the bug is already reported yet :-( ) When I submit the ticket, I get this message: Submission rejected as potential spam (Akismet says content is spam) Below is the ticket incorrectly reported as SPAM ==== How to Reproduce ==== While doing a GET operation on `/report/14`, Trac issued an internal error. '' Trac detected an internal error: ValueError: invalid literal for int(): '' Request parameters: {{{ {'id': u'14'} }}} User Agent was: `Opera/9.50 (Windows NT 5.1; U; en)` ==== System Information ==== || '''Trac''' || `0.11` || || '''Python''' || `2.4.4 (#1, Jan 25 2007, 13:04:51) ` [[br]] `[GCC 3.4.6 20060404 (Red Hat 3.4.6-3)]` || || '''setuptools''' || `0.6c8` || || '''SQLite''' || `3.5.4` || || '''pysqlite''' || `2.4.1` || || '''Genshi''' || `0.5` || || '''Subversion''' || `1.4.2 (r22196)` || || '''jQuery:''' || `1.2.3` || ==== Python Traceback ==== {{{ Traceback (most recent call last): File "/opt/trac2/lib/python2.4/site-packages/Trac-0.11-py2.4.egg/trac/web/main.py", line 423, in _dispatch_request dispatcher.dispatch(req) File "/opt/trac2/lib/python2.4/site-packages/Trac-0.11-py2.4.egg/trac/web/main.py", line 219, in dispatch data, content_type) File "/opt/trac2/lib/python2.4/site-packages/Trac-0.11-py2.4.egg/trac/web/chrome.py", line 726, in render_template stream.render(method, doctype=doctype, out=buffer) File "build/bdist.linux-i686/egg/genshi/core.py", line 179, in render File "build/bdist.linux-i686/egg/genshi/output.py", line 61, in encode File "build/bdist.linux-i686/egg/genshi/output.py", line 311, in __call__ File "build/bdist.linux-i686/egg/genshi/output.py", line 753, in __call__ File "build/bdist.linux-i686/egg/genshi/output.py", line 592, in __call__ File "build/bdist.linux-i686/egg/genshi/output.py", line 698, in __call__ File "build/bdist.linux-i686/egg/genshi/output.py", line 532, in __call__ File "build/bdist.linux-i686/egg/genshi/core.py", line 283, in _ensure File "build/bdist.linux-i686/egg/genshi/core.py", line 283, in _ensure File "/opt/trac2/lib/python2.4/site-packages/Trac-0.11-py2.4.egg/trac/web/chrome.py", line 779, in _strip_accesskeys for kind, data, pos in stream: File "build/bdist.linux-i686/egg/genshi/core.py", line 283, in _ensure File "/opt/trac2/lib/python2.4/site-packages/Trac-0.11-py2.4.egg/trac/web/chrome.py", line 768, in _generate for kind, data, pos in stream: File "build/bdist.linux-i686/egg/genshi/template/base.py", line 569, in _include File "build/bdist.linux-i686/egg/genshi/template/markup.py", line 299, in _match File "build/bdist.linux-i686/egg/genshi/template/markup.py", line 299, in _match File "build/bdist.linux-i686/egg/genshi/template/markup.py", line 246, in _match File "build/bdist.linux-i686/egg/genshi/template/base.py", line 543, in _exec File "build/bdist.linux-i686/egg/genshi/template/base.py", line 533, in _eval File "build/bdist.linux-i686/egg/genshi/template/base.py", line 496, in _eval File "build/bdist.linux-i686/egg/genshi/template/base.py", line 551, in _flatten File "build/bdist.linux-i686/egg/genshi/core.py", line 283, in _ensure File "build/bdist.linux-i686/egg/genshi/path.py", line 141, in _generate File "build/bdist.linux-i686/egg/genshi/template/base.py", line 569, in _include File "build/bdist.linux-i686/egg/genshi/template/markup.py", line 235, in _strip File "build/bdist.linux-i686/egg/genshi/template/base.py", line 543, in _exec File "build/bdist.linux-i686/egg/genshi/template/base.py", line 533, in _eval File "build/bdist.linux-i686/egg/genshi/template/base.py", line 496, in _eval File "build/bdist.linux-i686/egg/genshi/template/base.py", line 551, in _flatten File "build/bdist.linux-i686/egg/genshi/core.py", line 283, in _ensure File "build/bdist.linux-i686/egg/genshi/path.py", line 141, in _generate File "build/bdist.linux-i686/egg/genshi/template/base.py", line 569, in _include File "build/bdist.linux-i686/egg/genshi/template/markup.py", line 235, in _strip File "build/bdist.linux-i686/egg/genshi/template/base.py", line 543, in _exec File "build/bdist.linux-i686/egg/genshi/template/base.py", line 520, in _eval File "build/bdist.linux-i686/egg/genshi/template/base.py", line 286, in _eval_expr File "build/bdist.linux-i686/egg/genshi/template/eval.py", line 180, in evaluate File "/opt/trac2/lib/python2.4/site-packages/Trac-0.11-py2.4.egg/trac/ticket/templates/report_view.html", line 120, in <Expression u"cell.value != 'None' and format_date(int(cell.value)) or '--'"> <td class="date" py:attrs="td_attrs">${cell.value != 'None' and format_date(int(cell.value)) or '--'} ValueError: invalid literal for int(): }}}

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[swap] How to override swap now?
by Terry G 18 Aug '08

18 Aug '08

I notice that Boost now has it's own boost::swap and that it has had recent trouble before the 1.36 release. How should a user/developer like me implement a custom swap so that users get the benefit of my::swap, then boost::swap, and finally std::swap without putting too much burden on my user. So I have three questions. (1) How should user-code use boost:swap? (2) How should boost-developers use boost::swap()? (3) How should non-boost-developers provide swap()? Consider my motivating (to me) example... Let's say I have a move library that works, hypothetically. namespace my { // These are defined and actually work, hypothetically. template <class T> struct is_moveable; template <class T> struct move_from { }; template <class T>T& move(T& x); template <class T> void swap(T& x, T& y) { T tmp = move(x); x = move(y); y = move(tmp); } // swap } // namespace my If the user does this... using namespace std; using namespace boost; using namespace my; And then somewhere in his code... HisType a = MakeA(); HisType b = MakeB(); swap(a, b); // Unqualified? Or should the user specify a namespace? Which one? What I wish would happen would be... If the user has his own swap(HisType, HisType) invoke that. Otherwise, if HisType.swap() exists, then use that. Otherwise, use my::swap() if its "better" than boost::swap Otherwise, use boost::swap(), if its "better" than std::swap Otherwise, just use std::swap(). Sorry about all the ambiguity. But that's the real problem, isn't it? terry

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[function_types] Removing class type from member function signature.
by Fabio Fracassi 18 Aug '08

18 Aug '08

Hi, I'm currently trying to wrap (or forward) a call to boost::signal<A_func_Signature>::connect(), to - amongst other things - insulate users from using boost::bind. So what I have is something like this: template< typename Signature, class Reciever > void connect( const signal_id& id, const Signature& sig, const Reciever* rcv ) { typedef ???? AdaptedSignature; get_signal< AdaptedSignature > ( id ) -> connect(boost::bind(sig, rcv, _1)); } now this code is supposed to be called like this: connect( some_signal_id, &SomeClass::some_member, someClass_instance ); where SomeClass::some_member has the same function signature as the signal which is associated with some_signal_id. e.g. boost::signal<void (bool)> signal; struct SomeClass { void some_member(bool b); }; So my question is how can I construct the "AdaptedSignature" type from the template deduced "Signature"? From what I gather from the documentation, boost function_types might hold the answer to my question, but I cannot figure out how. So is what I am trying to do possible, and is function_types the right tool? TIA Fabio

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[scoped_ptr] Transferring pointers to scoped_ptr member
by Christian Larsen 18 Aug '08

18 Aug '08

Hi, This is just make sure I'm not being too careful in this situation. So please confirm whether this is correct. I have a class with two scoped_ptr members, and I want to pass two pointers to the constructor, which will then transfer the ownership of both to the two member scoped_ptrs. I assume the following is not safe: (I didn't try compiling; using namespace boost and std.) struct B {}; class A { public: A(B* b1, B* b2) : b1_(b1), b2_(b2) {} private: scoped_ptr b1_; scoped_ptr b2_; }; // Create an A this way: A a(new B, new B); Is it correct that this could fail if one of the 'new B's throw, thus leaking before the constructor ever started? If that is so, is this then the correct way to achieve the same in a safe manner? struct B {}; class A { public: A(auto_ptr& b1, auto_ptr& b2) : b1_(b1.release()), b2_(b2.release()) {} private: scoped_ptr b1_; scoped_ptr b2_; }; // Create an A this way: A a(auto_ptr(new B), auto_ptr(new B)); Best regards, Christian

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[python] partially resolved: the never ending story of vc8/win32 linker settings desaster
by Markus Werle 18 Aug '08

18 Aug '08

Hi! So now since I wasted 2 days figuring out the interaction of Python with boost::python and Visual Studio 2005 SP1 (VC8) I finally managed to resolve the "VC8/Debug Crashes" problem. To be honest: I am shocked and I need someone to explain why things are intentionally broken the way they are. All boost libraries play nicely with *any* build system, but the settings for Boost.Python are twisted in ways that make me feel absolutely uncomfortable. Admittedly some of the headaches have their reason inside Python itself and somehow Visual Studio plays ugly, too, but IMHO it is time to rework the settings shipped with Boost.Python. I managed to resolve some of the troubles I had with VS2005. If you try to run a debug version of Boost.Python with Debug-Python you are on your own: Boost.Python(Debug) deliberately links to Python(Release) which is the source of major headache: 1. With VS2005 it is NOT a GoodIdea(TM) to mix different types of binaries for one executable, since the (stupid) linker of vs2005 succeeds without error sometimes creating executables that fail to be debugged and/or crash at random points during execution. Summary: VC8 linker sucks in many aspects, so don't do that. This is a request to change the settings of the debug version Boost.Python, even if this forces the user to download the python sources. What do you think? 2. You can, of course, build Python with _DEBUG settings. This again breaks everything: Python-2.5.2, sets Py_DEBUG and then in file Include/object.h, line 58 decides that 54 /* Py_DEBUG implies Py_TRACE_REFS. */ 55 #if defined(Py_DEBUG) && !defined(Py_TRACE_REFS) 56 #define Py_TRACE_REFS // WE HAVE A PROBLEM HERE!!!!!!!! 57 #endif Autodefined Py_TRACE_REFS itself yields Py_InitModule4 be renamed to Py_InitModule4TraceRefs in modsupport.h: #ifdef Py_TRACE_REFS /* When we are tracing reference counts, rename Py_InitModule4 so modules compiled with incompatible settings will generate a link-time error. */ ... #define Py_InitModule4 Py_InitModule4TraceRefs #endif Unfortunately two things lead to a headache here: First, boost::python::detail::init_module *always* calls Py_InitModule4 regardless of the compiler settings, which I consider critical here. See libs/python/src/module.cpp for what I mean. Second, vc8 linker - for reasons beyond my limited horizon - during search of symbols in my self-created python_d.lib/dll fails to find Py_InitModule4, requested by boost::python::detail::init_module, but happens to find python.lib/dll in the same directory and (BOOM) silently links against python.lib/dll (OUCH!) which yields a truly broken executable, the nightmare of debugging stuff that should not have compiled. I suspect Boost.Python settings to be resposible for this. Please correct me if I am wrong here (of course I may have missed something): Summary so far: If you want to debug an embedded Boost.Python/Python with vc8 you have to fetch the Python sources, change file Include/object.h, line 56 such that 54 /* Py_DEBUG implies Py_TRACE_REFS. */ 55 #if defined(Py_DEBUG) && !defined(Py_TRACE_REFS) 56 // #define Py_TRACE_REFS // WE HAVE A PROBLEM HERE!!!!!!!! 57 #endif then after rebuilding the "Debug" version of PCbuild8\pcbuild.sln go to your own project, Open the project settings linker settings and add python.lib to the "Ignore Specific Library" section. Copy the python_d.dll and .lib files to your project and everything is fine. Phew. Done. Compiles. Runs. Does not Crash. Don't you think we can do better? IMHO the content of libs/python/src/module.cpp belongs into a header that allows users to control its behaviour and that nicely interacts with the original Pythion settings. To be resolved: I failed to create a static executable that statically links to boost::python and Python, since boost::python static libs ask for python.lib/dll symbols beginning with __imp__ instead of taking those in my self-named libpython-mt-sgd.lib. Can you provide a resolution for this task? Boost.Build settings? Wrong library included? Markus

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Filesystem, serialization, character encoding and portable software
by Mathieu Peyréga 18 Aug '08

18 Aug '08

Hello, I'm currently writting an open source and portable (Win32 / OS X / Linux) software, and i'm using parts of boost libraries, especially for the issue described here : - boost serialization - boost filesystem At some point, i'm storing a directory name (as a std::string) into a xml file through boost serialization library. The encoding occurs on a windows platform, and as far as i can understand (i'm really new to all these character set issues) it seems to be done in win1252 character set. One of the directory "stored" is named "français" (notice the cedilla on the c) and is the issue.. When i load this file back on a linux or osx platform, and try to access files in the "français" directory, i got an error of the kind (no such directory)... because the encoding of the ç with cedilla seem to be wrong... (everythong works fine if i put "francais" everywhere without cedilla) Is there somewhere a good starting document for character set for dummies with tutorials or stuff like that ? How would you suggest i correct the issue (while keeping the "ç") ? Altought, I understand this is not completely boost issue... But it seems to have so many "hidden" functions that i'm wondering if the libraries would have something to do that that i missed... Regards, Mathieu -- http://www.incub.net/

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Boost 1.36.0 release notice
by Beman Dawes 18 Aug '08

18 Aug '08

Boost 1.36.0 has been released and is available from SourceForge. See http://sourceforge.net/projects/boost/ This release include four new libraries: * Accumulators: Framework for incremental calculation, and collection of statistical accumulators, from Eric Niebler. * Exception: A library for transporting of arbitrary data in exception objects, and transporting of exceptions between threads, from Emil Dotchevski. * Units: Zero-overhead dimensional analysis and unit/quantity manipulation and conversion, from Matthias Schabel and Steven Watanabe * Unordered: Unordered associative containers, from Daniel James. Updated libraries include Asio, Assign, Function, Hash, Interprocess, Intrusive, Math, MPI, Multi-index Containers, PtrContainer, Spirit, Thread, Wave, and Xpressive. The release managers were Beman Dawes, Rene Rivera, and Daniel James. One note of caution: the initial SourceForge release files were missing some of the documentation. If you downloaded before 16:00 UTC, August 14th, please download again to be sure to get the full distribution. Sorry for the inconvenience! --Beman Dawes PS: The 1.36.0 version of the web site should be up within a few hours. If you can't wait, see http://beta.boost.org now!

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[filesystem] convenience_test.cpp question
by Olaf Peter 18 Aug '08

18 Aug '08

Hi, on studying the boost's files I found in convenience_test.cpp this statement: BOOST_CHECK( fs::extension("a/") == "." ); Why this? IMO it's not clear why this should be correct. This means that a leaf path has a file extension. On directory's view this is not equal to the current dir notation. Thanks, Olaf BTW, what about the support on hard- and softlinks mentioned in this list some times ago?

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[filesystem] Changes in Boost 1.36 not documented?
by Anteru 18 Aug '08

18 Aug '08

Hi, I've just upgraded to Boost 1.36, and I had to change some code because the directory iterators ->leaf () function has changed. Looking at the docs (http://www.boost.org/doc/libs/1_36_0/libs/filesystem/doc/index.htm#Change-h…) there is no information what has changed in 1.36 and how to port 1.35 code over to it. Is this information available somewhere else? Cheers, Anteru

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